一応、現象の起きたテーブルとクエリを貼っておきます。
create table [dbo].[M_APHeartBeat] (
C_ServerID nvarchar(16) not null
, D_BeatDT datetime not null
, primary key (C_ServerID)
);
MERGE
INTO M_APHeartBeat AS A
USING (SELECT ‘PROC01’ AS C_ServerID) AS B
ON (A.C_ServerID = B.C_ServerID) WHEN MATCHED THEN UPDATE
SET
D_BeatDT = GetDate() WHEN NOT MATCHED THEN
INSERT (C_ServerID, D_BeatDT)
VALUES (B.C_ServerID, GetDate())
;